<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>

  <body>
    <div id="app">
      <div>
        <p>请选择你要购买的书籍</p>
        <ul>
          <li v-for="v of arr" :key="v.name">
            {{ v.name }} <button @click="v.count++">买书</button>
          </li>
        </ul>
        <table border="1" width="500" cellspacing="0">
          <tr>
            <th>序号</th>
            <th>书名</th>
            <th>单价</th>
            <th>数量</th>
            <th>合计</th>
          </tr>
          <tr v-for="(v, i) of arr" :key="v.name">
            <td>{{ i + 1 }}</td>
            <td>{{ v.name }}</td>
            <td>{{ v.price }}</td>
            <td>{{ v.count }}</td>
            <td>{{ v.price * v.count }}</td>
          </tr>
        </table>
        <p>总价格为: {{ total }}</p>
      </div>
    </div>
    <script src="./vue.js"></script>
    <script>
      const app = new Vue({
        el: '#app',
        data: {
          arr: [
            {
              name: '水浒传',
              price: 107,
              count: 0,
            },
            {
              name: '西游记',
              price: 192,
              count: 0,
            },
            {
              name: '三国演义',
              price: 219,
              count: 0,
            },
            {
              name: '红楼梦',
              price: 178,
              count: 0,
            },
          ],
        },
        computed: {
          total() {
            return this.arr.reduce((sum, v) => {
              return sum + v.price * v.count;
            }, 0);
          },
        },
        // methods: {
        //   buy(bookObj) {
        //     bookObj.count++;
        //   },
        // },
      });
    </script>
  </body>
</html>
